In adaptive signal processing, a variety of apparatus has been proposed for arriving at the desired signal output. In U.S. Pat. No. 4,236,158, issued Nov. 25, 1980, and entitled "Steepest Descent Controller For An Adaptive Antenna Array", apparatus for producing a steepest descent control is disclosed. The steepest descent control is a very desirable method of achieving the required output signal, but the apparatus can be relatively expensive and complicated. A second type of control, known as an accelerated gradient control, is disclosed in an article entitled "Improved Feedback Loop for Adaptive Arrays", Proceedings of the IEEE on Aerospace and Electronics Systems, Vol. AES-16, No. 2, March 1980, by R. T. Compton, Jr. Again, the accelerated gradient control can be relatively expensive. The cost of the above systems can be reduced in accordance with apparatus disclosed in U.S. Pat. No. 4,286,268, issued Aug. 25, 1981, entitled "Adaptive Array with Optimal Sequential Gradient Control". In this patent many of the components are time-shared to substantially reduce the costs thereof.
The use of weight dithering in adaptive arrays has been suggested previously to achieve low cost implementation by eliminating IF hardware, at the expense of slower and often less stable convergence and narrower bandwidths.